My TI-83 calculator doesnt allow me to do this, but using Windows calculator, I can compute the factorial of say 5.8. What does this mean and how does it work?

  • 2
    $\begingroup$ As I recall, these calculators can compute factorials of half-integers. But yes, you need $\Gamma(z)$ in general. $\endgroup$ Nov 28, 2010 at 1:29
  • $\begingroup$ Out of interest, what value do you get for $5.8!$? If it's based on the gamma function, you would get around $496.606\ldots$. (Everyone's mentioned the gamma function here, which is the most likely candidate, but there are other possible extensions of the factorial function to non-integers) $\endgroup$ Jul 6 at 11:04

1 Answer 1


Perhaps you're looking for the Gamma function. It restricts to the usual factorial on natural numbers.

Wikipedia's article on Gamma function


You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .